Acquired immune deficiency syndrome (AIDS) is recognized as one of the greatest health threats facing modern medicine. There is, as yet, no cure for this disease.
In 1983-1984, three groups independently identified the suspected etiological agent of AIDS. See, e.g., Barre-Sinoussi et al. (1983) Science 220:868-871; Montagnier et al., in Human T-Cell Leukemia Viruses (Gallo, Essex & Gross, eds., 1984); Vilmer et al. (1984) The Lancet 1:753; Popovic et al. (1984) Science 224:497-500; Levy et al. (1984) Science 225:840-842. These isolates were variously called lymphadenopathy-associated virus (LAV), human T-cell lymphotropic virus type III (HTLV-III), or AIDS-associated retrovirus (ARV). All of these isolates are strains of the same virus, and were later collectively named Human Immunodeficiency Virus (HIV). With the isolation of a related AIDS-causing virus, the strains originally called HIV are now termed HIV-1 and the related virus is called HIV-2. See, e.g., Guyader et al. (1987) Nature 326:662-669; Brun-Vezinet et al. (1986) Science 233:343-346; Clavel et al. (1986) Nature 324:691-695.
A great deal of information has been generated about the HIV virus; however, to date an effective vaccine has not been identified. Several targets for vaccine development have been examined including the Env and Gag gene products encoded by HIV. Gag gene products include, but are not limited to, Gag-polymerase and Gag-protease. Env gene products include, but are not limited to, monomeric gp120 polypeptides, oligomeric gp140 polypeptides and gp160 polypeptides.
Use of HIV Env polypeptides in immunogenic compositions has been described. (see, e.g., U.S. Pat. No. 5,846,546 to Hurwitz et al., describing immunogenic compositions comprising a mixture of at least four different recombinant viruses that each expresses a different HIV env variant; and U.S. Pat. No. 5,840,313 to Vahlne et al., describing peptides which correspond to epitopes of the HIV-1 gp120 protein). In addition, U.S. Pat. No. 5,876,731 to Sia et al, describes candidate vaccines against HIV comprising an amino acid sequence of a T-cell epitope of Gag linked directly to an amino acid sequence of a B-cell epitope of the V3 loop protein of an HIV-1 isolate containing the sequence GPGR. However, none of these Env polypeptide base compositions has been shown to provide a sufficient protective immune response to be useful for an efficacious vaccine. Recently, G. Krashias et al. (Vaccine. 28:2482-2489, 2010) described a vaccine comprising gp140 and CARBOPOL™. G. Krashias et al. found that the CARBOPOL™ provided an improved immune response over alum as an adjuvant. However, G. Krashias et al. found no detectable binding between gp140 and CARBOPOL™.